Automatic transmissions, particularly those for motor vehicles, cover planetary assemblies, which are switched by way of friction and/or control elements, such as clutches and brakes, and generally are equipped by choice with a bridging clutch with a starting element and linked to an underlying slip effect, such as a hydrodynamic torque converter or a Foettinger coupling.
Such transmission is based on an EP 0 434 525 A1. It basically consists of a drive shaft and an output shaft, which are arranged parallel to each other; one concentrically to the output shaft, arranged as a double planetary gearset, and five switch elements in the form of three clutches and two brakes, whose optional locking, always in pairs, and in each case, determines the various gear transmissions between the drive shaft and the output shaft. Herein the transmission consists of a wheel set series and two power modes so that, by selective pair gearing, six forward gears are obtained from the five switching elements.
Herein within the first power mode of the two clutches, it is required for transmission of the torque from the wheel set series to the two elements of the double planetary gearset. They are essentially arranged behind the wheel set series in direction of the double planetary gearset in the direction of the power flux. An additional clutch is provided in the second power mode that loosely connects this one with a further element of the double planetary gearset. The clutches are thus arranged in such a manner that the inside plate carrier forms the output.
Furthermore, a compact multi-step reduction gear transmission of the planetary type construction, especially well-known for motor vehicles, which displays two planetary wheel sets and a wheel set series as well as three clutches and two brakes, is known from U.S. Pat. No. 6,139,463. This well-known multi-stage gear has two clutches C1 and C-3 for torque transfer at the first power mode from the wheel set series to both of the planetary wheel sets. In this way, the outer plate beam and/or the cylinder and/or piston and the compensation side of the clutch C-3 are linked with a first brake B-1. In addition, the interior plate beam of the third clutch C-3 is connected to the cylinder and/or piston and the compensation side of the first clutch C-1, whereby the interior plate beam of the first clutch C-1 is arranged at the output side and is connected with a sun wheel of the third planetary wheel set.
Furthermore, a multi-step reduction gear transmission is also known from the patent holder of the DE 199 49 507 A1, which is equipped with two wheel set series on the drive shaft that cannot be switched and which, on the output side, produce two revolutions which, in addition to the revolutions of the drive shaft, act selectively upon a switchable dual planetary wheel set that operates by way of selectively shutting off the used switch elements in order to switch from one gear of the two operating switch elements into the next following higher or lower gear of the two just engaged switch elements so that only one switching element has to be switched on or off.
DE 199 12 480 A1 is well known for its automatic, adjustable, motor vehicle transmission with three access planet sets as well as three brakes and two clutches for switching six forward and a reverse gear and with a drive as well as an output shaft. The automatic, adjustable, motor vehicle transmission is constructed in such a manner that the drive shaft is connected directly to the sun wheel of the second planetary set and that the drive shaft is linked across the first clutch to the sun wheel of the first planetary set and/or can be connected across the second clutch with the fixed link of the first planetary set. Additionally or alternatively, the sun wheel of the first planetary set can be connected across the first brake with the housing the transmission and/or the fixed link of the first planetary set across the second brake with the housing and/or the sun wheel of the third planetary set across the third brake with the housing.
Moreover a multi-stage gear automatic transmission is well-known from the DE 102 13 820 A1 patent, includes an input path T1 of a first speed ratio; an input path T2 which has a larger speed ratio this input path T1; a planetary gearset of four elements, wherein the four elements are a first element, a second element, a third element, and a fourth element following an order of elements on a speed diagram; a clutch C-2 transmitting a rotation from the input path T2 to the first element S3; a clutch C-1 transmitting the rotation from the input path T2 to the fourth element S2; a clutch C-4 transmitting a rotation from the input path T1 to the first element; a clutch C-3 transmitting the rotation from the input path T1 to the second element C3; a brake B-1 engaging the fourth element; a brake B-2 engaging the second element and an output member coupled with the third element R3.
Within the scope of DE 101 15 983 A1, the patent holder describes a multi-stage reduction transmission that has a drive shaft, which is connected with a wheel set series by an output shaft that is linked to a lower switching set that has no more than seven switching elements through which selective switching through at least seven forward gears without parallel shifting is possible. The wheel set series is constructed of a planetary gearset series or maximally two non-switchable planetary wheel sets that are linked to the first connection planetary wheel set wherein the lower switching set is designed as a two-bar, four-shaft transmission with two adjustable lower switch planetary wheel sets and displays four idle shafts. The first idle shaft of this two-bar four-shaft transmission is connected to the first switch element, the second idle shaft in the second and third switch elements, the third idle shaft to the fourth and fifth switching elements and the fourth idle shaft is connected to the drive shaft. According to this invention, for a multi-stage, reduction gear with a total of six shifting elements it is suggested additionally connect the third idle shaft or the first idle shaft of the lower switch set to a sixth switching element. The invention suggests that the third idle shaft of the multi-stage reduction gear transmission with a total of seven switch elements should be additionally connected with a sixth switching element D′ and that the first idle shaft should be connected with a seventh switch element.
furthermore, the Applicant describes the multi-stage reduction gear transmission with at least seven gears within the scope of the DE 101 15 987 patent. In addition to the drive shaft and the output shaft, this transmission consists of a non-switchable wheel set series and an adjustable connecting lower switch set in the form of a two-bar, four-shaft transmission. The wheel set series consists of a first planetary gearset which, in addition to the feed number of revolutions of the drive shaft, provides a second number of revolutions that can be selectively switched to a lower switch set. The lower switch set consists of two adjustable planetary gearsets which, together with the six switch elements, provide for at least seven gears, wherein two power mode, output passages are created. Thus with each switching operation in a favorable manner, continuous group shifting is avoided. Furthermore, a 9-gear-multi-stage, reduction gear is well-known from DE 29 36 969; it comprises eight shifting elements and four wheel sets.
The automatic adjustable car transmissions in planetary design methods are generally described from the state of the art technological point of view and are subject to a continuous development and improvement process. In this way, such transmissions should display a sufficient number of forward gears as well as a reverse gear to provide for a well-suited gear reduction for motor vehicles displaying an overall flexibility as well as a favorable progressive ratio. In addition, these transmissions should make a high takeoff reduction possible in a forward gear and maintain a direct gear operation and also be suited for passenger cars, as well as commercial vehicles. In addition, these transmissions should require a lower manufacturing cost and especially a small number of shifting elements and to avoid double shifting during sequential gear shifts so that with shifts in a defined gear group only one element at a time will be shifted.
This invention is basically intended as a multi-stage reduction gear transmission of the above described type in which the manufacturing cost is optimized and, furthermore, the effectiveness of the main driving gears regarding losses due to drag and toothing. In addition, in case of the multi-stage reduction gears, according to this invention, small moments which have an effect on the shift elements and the planetary sets, as well as on the shaft rotations, shift elements and planetary sets are kept as low as possible. Moreover, the number of gears, as well as the gear flexibility, should be increased so that the seven forward gears and at least one reverse gear are used to an advantage. Also according to the invention, the transmission should be suitable for any vehicle; in the transmission should be suitable for vehicles of any type of design, especially in a front transverse arrangement.